Sealing coat for tablets and the like



s 041 243 SEALING COAT Fon TABLETs ANn rim tum Norio Sugimoto, Otsu-shi, Shiga-lren, lsamu Utsumi,

Sakyo-ku, Kyoto-shi, and Tadao Ida, Nara-hen, Japan,

This invention relates to a sealing coat for oral medicaments in the form of tablets, pills, granules and like to protect their contents, and to articles sealed with the coat.

It is known to give a sealing coat to compressed tablets to protect their contents from moisture before the tablets are covered with a plurality of coatings of sugar syrup to which powdered filler is added during the intermediate drying after the application of each coating. A sealing coat is also required when tablets are coated with a watersoluble film-forming material such as gelatin. Sometimes, such a sealing coat is applied to a tablet containing unstable substances such as vitamins, hormones and antibiotics to prevent deterioration. Heretofore, such a sealing coat has consisted of a film forming material insoluble in water such as shellac, nitrocellulose or polyvinyl acetate. Such a coat is practically insoluble in water and dilute acid, and therefore sufiicient thickness of the coat for elimination of absorption of moisture and/ or oxygen results in an increase in disintegration time in the gastric juices.

The object of this invention is to provide a new and improved sealing coat for oral medicaments in the form Patented .lune26, reea lice 2 dine polymers and copolymers which are soluble in dilute acids but ins0luble in water may be used,

The therapeuticmaterial to be sealed with these resins may be coatedby a usual method using a solution of one of the said polymers. H

The solutions are conveniently prepared by dissolving the polymers in solvents such as methanol, ethanol, chloroform, carbon tetrachloride and benzene to the extent of 5% to 30%.

The solutions are then applied by pouring under the rotation of a coating-pan wherein-tablets or the like are placed. Alternatively, the application may be carried out by spraying or dipping. The solvents are allowed to evaporate whereby the sealing coat of the invention are formed. In the said manner several layers of the filmforming polymer may be applied successively until a required thickness of the coat is obtained. In our experiments about 50 to 250 microns of thickness of the coat are preferable to give a sutiicient resistance to moisture and/or oxygen. Such a thickness of the coating material generally disintegrates from 5 to 20 minutes in the acidic medium of the stomach.

The sealed medicaments of the invention show a high degree of stability on storage. The inventionis, therefore, particularly suitable for use in the manufacture of tablets and similar articles containing unstable active substances such as vitamins, hormones and similar substances. More particularly, it is suitable for use in the sealing of compressed tablets and like containing hygroscopic active of tablets, pills, granules and like whereby these medica-j.

ments are protected from moisture and/or oxygen or other substances which tend to cause variations in their medicinal value without any increase in disintegration time in gastric juices.

According to the invention, compressed tablets and similar articles are sealed with a water-insoluble but acidsoluble film-forming polymer selected from the group con-' sisting of poly-Z-vinylpyridine, poly-4-vinylp-yridine, poly: f

described. The polymers employed in this invention may be prepared by polymerizing said vinylpyridine monomer alone or with the said co-mcnomer according to the known method. Polymerization may be carried out under a standard condition which is known to those skilled in the art. Among many kinds of polymerization technique, emulsionor solution-polymerization is conveniently applicable. For example, the recipe which consists of one of the vinylpyridine monomers or its mixture with the co-monomer, methanol and a small amount of benzoylperoxide is heated at a temperature of 20 to 70 C. until the conversion is essentially completed and then is fractionated by partial precipitation with a caustic alkali. Another example of the preferred recipe is the vinyl-pryidine monomer alone, a dilute acid such as hydrochloric acid and sulfuric acid, and a small amount of potassium persulfate. The copolymers may also be prepared using a recipe whichconsists of a mixture of the vinylpyridine and the co-monomer, dilute sulfuric acid, polyoxyethylene monostearate and a small amount of potassium persulfate. The production of such vinylpyridine resins themselves are not a part of this invention and any of said vinylpyrimaterials such as powdered extracts, bile salts, liver extracts and some colloidal materials.

The following examples will serve to indicate and illustrate more specifically the nature of this inverition without limiting it to the details set forth therein:

EXAMPLE 1 in distilled water and artificial gastric juice are shown in Table 2.

EXAMPLE 2 A mixture of each of the following pharmaceutical compositions A, B and C is compressed into a tablet respectively, in which a slugging method is applied to A and B while in C, a wet-granulation method, using methanol is applied.

Formula A:

Mg. Acetylsalicylic acid Starch 15 Formula B:

Acetylsalicylic acid 5O Antipyrin 30 Phenacetin 30 Starch 38 Magnesium stearate 2 3 4: Formula C: Table 3 Mg. Thiamine monomtrate 1 5 Typeof ggg g Thickness A b ag d 30 Formula polymer Solvent weight, inmicrons Starch 20 5 Lactose I 55 1 d 5 7 119.0 Polyvmy pyrro 1 one 1.. 10 127.5 Tale 4 10 80.8 10 57.3 Magnesium steal-ate 1 10 84,3 3 ill"? A sealing coat is applied in the same manner as ('10- Table 4 scribed in Example lunder the conditions as shown in Table 3. Both types of coated 'and uncoated tablets 15 F 1 Type f 10d 20d 39d 44d ormua o ays, ays ays, ays, are aged 1n an atmosphere at 37 C. and 85% relat1ve polymer percent percent percent percent humidity, respectively.

Salicylic acid content formed by decomposition of 403 1537 29.50 410 acetylsahcylic and an A and B are shown 1n Tables 4 and Z-gg g- 3 g- 5, respectively, and the percent of the original amount 1 3 of th1am1ne and ascorbic 301d remalmng 1n tablets are shown in Table 6.

Table 1--Recz'pes V y py- N0. Vinylpyridine (g.) Comonomer (g.) Solvent (g.) Catalyst (g.) Emulsi- Temp. Time Limiting ridine fier (g.) 0. (hrs.) viscosity content (percent) 1 Z-Vinyl, l %H2SO4, 184.-.. 50 10.3 0.69 2 2-vinyl,5.3- V. acetate, 8.6 CHSOHA 55 23.5 0.11 98.3 3 2-vinyl,2 Acrylonitrlle, 1.1. 10%114s04,20 00-70 3.0 0.45 91.8 4 do-.-. Methyl acrylate, 1.7- H01, 8 00-70 3. 0 0. 22 93. 4 5 2-vinyl,106 Styrene, 10.5 10%H4SO4,100 50 33.4 1.87 75.5 0 4- yl, 5 .P.O., 0.1.- 50 2.0 0.20 7 4-vmyi, 238 V. acetate, 34.4 011501116 B.P.O., 0.9.. 50 19.2 0.389 97.2 8 4-vinyl, 15.4-- Acrylonitrlle, 11.0. C 4011,10 B.P.O., 0.2. 50 6.3 0.60 97.4 9 4-vinyl, 23.8-- Methyl acrylate, 17.2 CHSOH,16 B.P.O.,0.4 50 15.0 1.05 90.8 10 do Styrene, 20.8 10%H4SO4, 200..-- K2S2OB, 0.4 0.8 50 7.0 1.08 92.5 11..." 2-1nethyl-4-vinyl, 23.8 .do do 50 49.0 1. 04 12 do V. acetate, 34.4 0138011, 16 B.P.O., 50 19.2 0.389 97.2 13 2-methyl-4-vinyi, 15.4-. Acrylonitnle, 11.0. CHzOH, i0 B.P.O., 50 6.3 0.69 97.4 14 2-methyl-4-vinyl, 23.8.- Methyl acrylate, 17.2 CHaOH, B.P.O., 50 15.6 1.05 90.8 15 doyr KQSEOB, 7.0 1.08 92.5 10.- 5-0thyl-2-v1nyl, 0.7- KtSzOs, 50 1.0 2.04 17 do V. acetate, 4.3. X28208, 9.0 0. 72 81.2 18. 5-ethyl-2-viny1,40.0 Acrylonitrile, 15.9. B.P.O., 70 2.0 1.21 55.9 19-... 5-etl1y1-2-viny1, 20.0.- Methyl acrylate, 17.2-..- 3.2.0., 50 24.0 0.83 80.8 20 5-ethyi-2-vinyl, 200.0 Styrene, 100.0 B.P.0., 40.0 0.80 57.2

1 Room temperature.

Table 2 Table 5 Coating solution Disintegration time Formula Type of 10 days, 16 days, 22 days, 23 y Thick. v polymer percent percent percent percent No.oi co at ing C ness o m d A m I 55 ma SI 3. 0110611- in IS 1 G I l (313.

Solvent tration, (microns) water gastric B Uncoated 6&0 percent (hm) juice B... No. 1R 8. 9 9.1 9. 5 10.3 (mm) B No.20--- 7.3 7.8 7.8 8.8

C'HaOH... 20 202 4 5-10 0113011... 20 205 as 5-10 Table 6 CH3OH 20 201 4 5-15 0115011.. 20 209 2-3 5-10 0131011"- 20 180 4 .5-15 Thiamine Mononitrate Ascorbic Acid Form- Type of gg gg i 11mm" 10 days, 27 days, 47 days, 20 days, 38 days, 47 days, CHOHII 20 220 4 percent percent percent percent percent percent 0H30H-.. 20 240 4 01513011... 20 201 4 Uncoated 97.4 81.8 00.3 79.0. 55.5 43.5 0.18.-." 97.8 86.8 7 1 87.0 70.5 05.0 CHzOH..- 10 151 4 No. 20 98.9 88.3 75.7 90.0 75.0 08.0 01150151... 10 154 2-3 CH3OH 10 150 4 CH10H 10 112 4 15-10 0113011... 10 148 4 8-10 We cla m: I

10 159 4 1. A body of solid material having a film-forming 1g 2 gig protective coating thereon which is water insoluble and 10 207 4 H0 acad soluble, said coating being selected from the group 10 4 conslstmg of polyvinylpyn'dines and copolymers of vinylpyridines and a monomer selected from the group consisting of vinylaoetate, acrylonitiile, methyl acrylate and styrene.

2. A body according to claim 1 characterized in that said body is a tablet.

3. A body according to claim 1 characterized in that said body is a pharmaceutical composition.

4. A body according to claim 1 characterized in that said vinylpyridine is a 2-vinylpyridine.

5. A body according to claim 1 characterized in that said vinylpyridine is a 4-vinylpyridine.

6. A body according to claim 1 characterized in that said vinylpyridine is a Z-methyl-Swinylpyridine.

7. A body according to claim 1 characterized in that said vinylpyridine is a S-ethyl-Z-vinylpyridine.

8. A body according to claim 1 characterized in that 15 said coating is moisture resistant.

Transformulation to Coating, Gross et 211., Drug and Cosmetic Industry, v01. 86, No. 2, February 1960, pp. 170-171, 264, 288291. 

1. A BODY OF SOLID MATERIAL HAVING A FILM-FORMING PROTECTIVE COATING THEREON WHICH ISWATER INSOLABLE AND ACID SOLUBLE, SAID COATING BEING SELECTED FROM THE GROUP CONSISTING OF POLYVINYLPYRIDINES AND COPOLYMERS OF VINYLPYRIDINES AND A MONOMER SELECTED FROM THE GROUP CONSISTING OF VINYLACETATE, ACRYLONITRILE, METHYL ACRYLATE AND STYRENE. 